Method formvalidator

/**
 * Add unobtrusive JavaScript support for form validation.
 *
 * To enable form validation the form tag must have class="form-validate".
 * Each field that needs to be validated needs to have class="validate".
 * Additional handlers can be added to the handler for username, password,
 * numeric and email. To use these add class="validate-email" and so on.
 *
 * @return  void
 *
 * @since   3.4
 * @deprecated 5.0 Use the script directly
 */
public static function formvalidator()
{
    // Only load once
    if (isset(static::$loaded[__METHOD__])) {
        return;
    }
    Factory::getDocument()->getWebAssetManager()->useScript('form.validate');
    static::$loaded[__METHOD__] = true;
}